See above. Conversations can look lots of different ways. If you assume the worse, it's kinda hard to move on from that.

A lot of siblings talk about their sex lives [gasp] without talking to their spouse.

Fuck. She suggested bringing a third into the bedroom. That would be a dealbreaker in a lot of relationships. If the issue is talking to a perspective third without the wife, that is a rookie mistake that indicates the need for more communication and boundary setting.

The fact is, everyone has gone off about the incest, and the disgust around that has blinded everyone here from being reasonable or even concerning themselves with the husband's thoughts, motivations, feelings, or whatever on the matter.

**Hell, for all we know, it was a joke gone horribly horribly wrong.

Nothing from OP suggests she had any kind of follow up with her husband, and this forum has already convinced her to divorce him.**

There is literally nothing in the OP to suggest diddly shit about the other side of the story ... but this whole damn theread is basically about how much the husband's an incestuous monster offering his wife up to his brother.